I think that we, in general, are private and shy and paranoid.
Mind you, there was a small restaurant i went to in Tennesee while i was on business (solo) and when i said I was alone, the hostess brought me to a long table where a number of other solo diners (also on business) were sitting, saying how no one should have to be alone just because they were away from home.
It was unnerving at first, but the others at the table were friendly and we had a good meal, and left when we were done and joined by others..
It made me feel less "alone" in the world, and i went back there for every meal, every night, and sat with some old, some new.
I wish i could remember the name of the place.. it was jsut a greasy spoon, but it was about 12 years ago ..